diff options
| -rw-r--r-- | drivers/tty/serial/max310x.c | 126 |
1 files changed, 86 insertions, 40 deletions
diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c index 2a2c4ea16306..dc0e1ad351f9 100644 --- a/drivers/tty/serial/max310x.c +++ b/drivers/tty/serial/max310x.c @@ -609,57 +609,103 @@ static void max310x_batch_write(struct uart_port *port, u8 *txbuf, unsigned int spi_sync_transfer(to_spi_device(port->dev), xfer, ARRAY_SIZE(xfer)); } -static void max310x_handle_rx(struct uart_port *port, unsigned int rxlen) +static void max310x_batch_read(struct uart_port *port, u8 *rxbuf, unsigned int len) { - unsigned int sts, ch, flag; + u8 header[] = { port->iobase + MAX310X_RHR_REG }; + struct spi_transfer xfer[] = { + { + .tx_buf = &header, + .len = sizeof(header), + }, { + .rx_buf = rxbuf, + .len = len, + } + }; + spi_sync_transfer(to_spi_device(port->dev), xfer, ARRAY_SIZE(xfer)); +} - if (unlikely(rxlen >= port->fifosize)) { - dev_warn_ratelimited(port->dev, "Possible RX FIFO overrun\n"); - port->icount.buf_overrun++; - /* Ensure sanity of RX level */ - rxlen = port->fifosize; - } +static void max310x_handle_rx(struct uart_port *port, unsigned int rxlen) +{ + unsigned int sts, ch, flag, i; + u8 buf[MAX310X_FIFO_SIZE]; + + if (port->read_status_mask == MAX310X_LSR_RXOVR_BIT) { + /* We are just reading, happily ignoring any error conditions. + * Break condition, parity checking, framing errors -- they + * are all ignored. That means that we can do a batch-read. + * + * There is a small opportunity for race if the RX FIFO + * overruns while we're reading the buffer; the datasheets says + * that the LSR register applies to the "current" character. + * That's also the reason why we cannot do batched reads when + * asked to check the individual statuses. + * */ - while (rxlen--) { - ch = max310x_port_read(port, MAX310X_RHR_REG); sts = max310x_port_read(port, MAX310X_LSR_IRQSTS_REG); + max310x_batch_read(port, buf, rxlen); - sts &= MAX310X_LSR_RXPAR_BIT | MAX310X_LSR_FRERR_BIT | - MAX310X_LSR_RXOVR_BIT | MAX310X_LSR_RXBRK_BIT; - - port->icount.rx++; + port->icount.rx += rxlen; flag = TTY_NORMAL; + sts &= port->read_status_mask; - if (unlikely(sts)) { - if (sts & MAX310X_LSR_RXBRK_BIT) { - port->icount.brk++; - if (uart_handle_break(port)) - continue; - } else if (sts & MAX310X_LSR_RXPAR_BIT) - port->icount.parity++; - else if (sts & MAX310X_LSR_FRERR_BIT) - port->icount.frame++; - else if (sts & MAX310X_LSR_RXOVR_BIT) - port->icount.overrun++; - - sts &= port->read_status_mask; - if (sts & MAX310X_LSR_RXBRK_BIT) - flag = TTY_BREAK; - else if (sts & MAX310X_LSR_RXPAR_BIT) - flag = TTY_PARITY; - else if (sts & MAX310X_LSR_FRERR_BIT) - flag = TTY_FRAME; - else if (sts & MAX310X_LSR_RXOVR_BIT) - flag = TTY_OVERRUN; + if (sts & MAX310X_LSR_RXOVR_BIT) { + dev_warn_ratelimited(port->dev, "Hardware RX FIFO overrun\n"); + port->icount.overrun++; } - if (uart_handle_sysrq_char(port, ch)) - continue; + for (i = 0; i < rxlen; ++i) { + uart_insert_char(port, sts, MAX310X_LSR_RXOVR_BIT, buf[i], flag); + } - if (sts & port->ignore_status_mask) - continue; + } else { + if (unlikely(rxlen >= port->fifosize)) { + dev_warn_ratelimited(port->dev, "Possible RX FIFO overrun\n"); + port->icount.buf_overrun++; + /* Ensure sanity of RX level */ + rxlen = port->fifosize; + } - uart_insert_char(port, sts, MAX310X_LSR_RXOVR_BIT, ch, flag); + while (rxlen--) { + ch = max310x_port_read(port, MAX310X_RHR_REG); + sts = max310x_port_read(port, MAX310X_LSR_IRQSTS_REG); + + sts &= MAX310X_LSR_RXPAR_BIT | MAX310X_LSR_FRERR_BIT | + MAX310X_LSR_RXOVR_BIT | MAX310X_LSR_RXBRK_BIT; + + port->icount.rx++; + flag = TTY_NORMAL; + + if (unlikely(sts)) { + if (sts & MAX310X_LSR_RXBRK_BIT) { + port->icount.brk++; + if (uart_handle_break(port)) + continue; + } else if (sts & MAX310X_LSR_RXPAR_BIT) + port->icount.parity++; + else if (sts & MAX310X_LSR_FRERR_BIT) + port->icount.frame++; + else if (sts & MAX310X_LSR_RXOVR_BIT) + port->icount.overrun++; + + sts &= port->read_status_mask; + if (sts & MAX310X_LSR_RXBRK_BIT) + flag = TTY_BREAK; + else if (sts & MAX310X_LSR_RXPAR_BIT) + flag = TTY_PARITY; + else if (sts & MAX310X_LSR_FRERR_BIT) + flag = TTY_FRAME; + else if (sts & MAX310X_LSR_RXOVR_BIT) + flag = TTY_OVERRUN; + } + + if (uart_handle_sysrq_char(port, ch)) + continue; + + if (sts & port->ignore_status_mask) + continue; + + uart_insert_char(port, sts, MAX310X_LSR_RXOVR_BIT, ch, flag); + } } tty_flip_buffer_push(&port->state->port); |